Antioxidants and in vitro starch digestibility of coloured rice, and its effect on blood sugar and malonaldehyde in streptozotocin-nicotinamide-induced diabetic rats

Abstract

Diabetes mellitus (DM) is an autoimmune disease caused by abnormal regulation of blood sugar, with type 2 DM representing 90 - 95% of total DM incidence. One of the preventive measures to improve blood sugar control is the regulation of eating patterns. The purposes of the present work were therefore (1) to determine the proximate composition, carotene and anthocyanin contents, starch digestibility, and antioxidant capacity of Baturraden white rice, Baturraden organic brown rice, and Sirampog black rice; and (2) to determine the effect of feeding these rice on fasting blood sugar and malondialdehyde (MDA) production in diabetic rats. Sirampog black rice had higher levels of carotene and anthocyanin, and higher radical scavenging activity than Baturraden organic brown and white rice. In diabetic rats, Sirampog black rice (Δ = 153.80 mg/dL) could reduce fasting blood sugar more effectively than Baturraden organic brown rice (Δ = 124.48 mg/dL) and Baturraden white rice (Δ = 14.62 mg/dL). Diabetic rats treated with Sirampog black rice also presented the lowest MDA levels of 2.62 nmol/mL when compared with that of Baturraden organic brown rice (3.96 nmol/mL) and Baturraden white rice (10.14 nmol/mL). Based on these results, patients with DM are advised to consume Sirampog black rice. In the future, it is necessary to perform trials in patients with DM to determine the effect of Sirampog black rice on fasting blood sugar and diabetic weight loss.